/*********************************************************************
 * Copyright (C) 2002 Andrew Khan
 * <p>
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * <p>
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * <p>
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ***************************************************************************/

package jxl.biff.formula;

import jxl.Cell;
import jxl.biff.CellReferenceHelper;
import jxl.biff.IntegerHelper;
import jxl.common.Logger;


/**
 * A cell reference in a formula
 */
class SharedFormulaCellReference extends Operand implements ParsedThing {
    // The logger
    private static Logger logger =
            Logger.getLogger(SharedFormulaCellReference.class);

    /**
     * Indicates whether the column reference is relative or absolute
     */
    private boolean columnRelative;

    /**
     * Indicates whether the row reference is relative or absolute
     */
    private boolean rowRelative;

    /**
     * The column reference
     */
    private int column;

    /**
     * The row reference
     */
    private int row;

    /**
     * The cell containing the formula.  Stored in order to determine
     * relative cell values
     */
    private Cell relativeTo;

    /**
     * Constructor
     *
     * @param the cell the formula is relative to
     */
    public SharedFormulaCellReference(Cell rt) {
        relativeTo = rt;
    }

    /**
     * Reads the ptg data from the array starting at the specified position
     *
     * @param data the RPN array
     * @param pos the current position in the array, excluding the ptg identifier
     * @return the number of bytes read
     */
    public int read(byte[] data, int pos) {
        // Preserve signage on column and row values, because they will
        // probably be relative
        row = IntegerHelper.getShort(data[pos], data[pos + 1]);

        int columnMask = IntegerHelper.getInt(data[pos + 2], data[pos + 3]);

        column = (byte) (columnMask & 0xff);
        columnRelative = ((columnMask & 0x4000) != 0);
        rowRelative = ((columnMask & 0x8000) != 0);

        if (columnRelative && relativeTo != null) {
            column = relativeTo.getColumn() + column;
        }

        if (rowRelative && relativeTo != null) {
            row = relativeTo.getRow() + row;
        }

        return 4;
    }

    public int getColumn() {
        return column;
    }

    public int getRow() {
        return row;
    }

    public void getString(StringBuffer buf) {
        CellReferenceHelper.getCellReference(column, row, buf);
    }

    /**
     * Gets the token representation of this item in RPN
     *
     * @return the bytes applicable to this formula
     */
    byte[] getBytes() {
        byte[] data = new byte[5];
        data[0] = Token.REF.getCode();

        IntegerHelper.getTwoBytes(row, data, 1);

        int columnMask = column;

        if (columnRelative) {
            columnMask |= 0x4000;
        }

        if (rowRelative) {
            columnMask |= 0x8000;
        }

        IntegerHelper.getTwoBytes(columnMask, data, 3);

        return data;
    }


    /**
     * If this formula was on an imported sheet, check that
     * cell references to another sheet are warned appropriately
     * Does nothing
     */
    void handleImportedCellReferences() {
    }
}









